Reciprocating impact tool



Nm?, El, 1924.

D. H. LAMAR RECIPROCATING IMPACT Toor.

Filed Dec` 5 l921 2 Sheets-Sheet l INVENTOR ATTO RN EY D. H. LAMARRECIPROCATING I MPACT T001 Nav, ll, 1924.

Filed Dec. 5, 1921 2 Sheets-Sheet 2 ATTORNEY wn'NEssEs;

Patented Nov. 11, 1924.

UNITED STAT DAVID H. LAMAR, OF HUTCHINSON, WEST VIRGINIA.

RECIPROCATIN Gr IMPACT TOOL.

Application led December 3, 1921.

To all 'whom t may concern:

Be it known that I, DAVID I-I. LAMAR, a citizen of the United States,residing at Hutchinson, in the county of Marion and State of WestVirginia, have invented new and useful Improvements in ReciprocatingImpact Tools, of which the following is a specification.

This invention relates to electrically op erated mining machines of thatcharacter which may be used in the capacity of a pick, hammer, drill orthe like, and provides a construction wherein the motion of the plungerrod can be quickly and conveniently changed from a sliding to a combinedsliding and rotary motion as the occasion requires.

Another object of the invention resides in providing a machine of thischaracter which is very simple in construction, embodying ya minimum ofparts, but at the same time strong and durable, the parts being relatedto eliminate the jerks and rebounds which are experienced with the useof other tools of this character, and which often results in injury tothe user.

The nature and advantage of the invention will bebetter understood whenthe following detailed description is read in connection with theaccompanying drawings, the invention residing in the construction,combination and arrangement of parts as claimed.

In the drawings forming part of this ap-l plication, like numerals ofreference indicate similar parts in the several views, and whereinFigure 1 is a view in elevation constructed in accordance with theinvention.

Figure 2 is a longitudinal sectional view through the machine.

Figure 3 is a fragmentary view through the machine, showing the positionof the parts when it is desired to change the motion of the plunger foruse as a drill.

Figure 4 is a transverse sectional view taken on line 4-4 of Figure 2.

Figure 5 is a transverse sectional view taken on line 5-5 of Figure 2.

Figure 6 is a fragmentary sectional view of the inner casing showing thegrooves therein.

The machine forming the subject matter of the present inventioncomprises an outer casing 10 and an inner casing 11, the said casingsbeing spaced apart to define a cham- Serial No. 519,727.

ber for the reception of the solenoids 12 and 13 respectively. Thecasing 10 is eX- tended to provide a reduced end portion 14 therebydefining a shoulder 15, and the adjacent extremity of the inner casing11 is embedded in this shoulder as at 16. The outer ends of thesecasings are closed by a cap 17 equippedswith a handle 18. Supported bythe cover 17 is a switch box 19 in which is arranged a movable switchelement 20 which is controlled by a thumb lever 21 which is arranged injuXta-position to they handle 18.

Arranged to Operate within the casing 11 is a magnetic core 22 which isequipped with a packing ring 23 and also formed with an enlarged recess24 which opens at one end of the core as shown.A The recess 24communicates with a longitudinally disposed bore 25 extended through thecore 22 and also through the plunger rod 26 which has one end threadedinto the magnetic core. 0perating within the recess 24 is an air gate27, the latter cooperating with an air gate 28 controlling an opening 29in the cover 17, the construction and arrangement being such that thegates alternately open and close incident to the operation of themachine to maintain the hole being drilled or formed free from dust aswill be readily understood. However, when the machine is used as a pickor a hammer, as in contradistinction to a drill, the lock screw 30 isadjusted to render the gate 28 inoperative. Positioned within thereduced end portion 14 of the casing 10 is a buffer 31 and arranged adjacent this buffer is a guide block 32 having a bore through which theplunger rod 26 operates.

A. disk 33l is formed with a central opening to receive the hollow boss34 which projects from one end of the guide block 32 and threaded on thehollow boss is a ring 35. Surrounding the boss 34 and having one endbearing against the ring 35 is a coiled spring 36, the opposite endbearing against the disk 33 to hold the latter normally in contacting.engagement with the adjacent end of the yguide block 32. The adjacentfaces of the guide block 32 and the disk 33 are serrated, or in otherwords, formed with cooperating teeth to provide for a rigid lock betweenthese parts so that they are held immovably associated for a purpose tobe hereinafter described. The teeth of these parts are indicated aty 37.

Threaded into the reduced end of the casing 10 is a bearing 38 'for theplungerl rod. Supported by the outer end of the plunger rod andproviding a connection between the latter and the shank 39 of the toolto be used therewith is a cylindrical or sleevelike member 40, andsupported by this sleeve, is what I term a governor box 41 containingspaced contacts, 42 and 43 respectively and a movable contact 44 whichis pivoited at one end between the contacts 42 and 43. The movablecontact 44 supports a weight 45 at one end. rllhe contact 42 isconnected by means of a wire 47 with the solenoid 12, while the contact43 is connected by means of a wire 46, with the solenoid 13, while anintermediate wire 48 establishes connection between the switch 19 andthe movable switch element as illustrated. Arranged within the casing 11and supported by the casing 1? is a check spring 49 dis osed in the pathof movement of the magne ic core 22. 'The opposite end or' this core isrecessed to receive a cushioning element 50 which surrounds the plungerrod 26 which is adapted to be brought into contact with the ring 35 uponthe power stroke of the said rod 26. It will be noted that the magneticcore 22 further serves in the capacity of a weight to drive the rod 26with considerable torce on its power stroke.

The operation of the machine thus far described is as follows:

When the thumb lever 21 is depressed, the switch 19 is closed, therebyenergizing the movable switch element 44 which operates within thegovernor box 41. The movable switch element 44 which is weighted at oneend is arranged to oscillate and to alternately engage the contacts 42and 43 respectively, and in this manner alternately energizes thesolenoids 12 and 13 respectively. For instance, when the tool 39 carriedby the plunger rod 26 is brought into contact with the work, the suddenstop of the tool will cause the movable Contact 44 Ito oscillate or fallupon the contact 43, thereby energizing the solenoid 13 which would movethe magnetic core from the forward end ot the machine to the rear endthereof and return the plunger rod 26 to its initial position. then themagnetic core reaches the limit of its movement or travel in thisdirection. the movable contact 44 is automatically shifted intoengagement with the contact 42, thereby energizing the solenoid foranother power Stroke of the plunger rod 26. vIn Ethis manner, theoperation oi the machine is continued with the plunger rod reciprocatingthrough the guide 32. By reason of the construction and arrangement ofparts, it is obvious thalt a stroke of the plunger rod 26 is immediatelystopped upon striking the object and the solenoid 13 energized to returnthe plunger rod to its normal position, so that kicks and rebounds,which requently prove injurious to the operators of machines of thislkind are practically eliminated.

As above stated, the motion of the plunger can be changed to permit ofthe use of a drill, and Jfor this purpose, the guide block 32 isprovided with a radial bore 52 which receives a threaded bolt or thelike 53. The normal position of this bolt is that shown in Figure 2, andwhen it is desired to change the motion of the plunger rod for thepurpose stated, the bolt is threaded into a notch 54 formed in theplunger rod 26. This manifestly, locks the guide block 32 to the plungerrod 26, for movement therewith so that when the plunger rod 26 isretracted or moved within the casing 11, the disk 33 moves also with theplug within said casing. The casing 11 is Jformed with spiral grooves55, and operating in these grooves are projections 5G which radiate fromthe disk 33. Consequently, when the disk 33 is moved rwithin the casing11, the guide lock 32, disk 33 and plunger rod 26 is slightly rotated.rlhe teeth 37 carried by the guide block 32 and the disk 33 preventrelative movement between these parts while they are being moved wit-hinthe casing 11 for the purpose stated, but on the power stroke oi theplunger rod, the latter moves forwardly together with the guide block 32independently ci the disk 33. By reason of this construction, the drillis slightly turned with each operation, so as to prevent its cuttingedge striking in the same pit on each stroke, and thegrooves 55 aresodisposed as to completely revolve the plunger rod in about eight strokesof the latter.

While it is believed that from the foregoing description, the nature andadvan tages of the invention will be readily apparent, I desire to haveit understood that l do not limit myself to what is herein shown anddescribed, and that such changes may be resorted to when desired as fallwithin the scope of what is claimed.

What I claim is 1. A machine of the character described comprising acasing, a plunger rod arranged to reciprocate within tliecasing andprojecting from one end thereof, a guide through which said rod slides,means Jfor actuating said rod, means for securing the guide to the rodfor movement therewith, and cooperating means associated with the saidguide and casing, whereby the motion of said rod is changed from asliding to a rotary motion for the purpose speciied.

2. In a machine of the character described, a casing, a plunger rodprojecting from one end of the casing and arranged to reciprocatetherein, a normally stationary guide arranged within the easing andthrough which said rod slides, means for operating said rod, means forsecuring the guide to said rod for movement therewith, a disk normallyarranged in face to face Contact with said guide, yieldable means forholding said parts so associated, said casing having spiral grooves, andmeans carried by said disk andmovable Within said grooves to change themotion of said rod from a slid- 10 ing to a rotary motion When said rod.moves in one direction.

In testimony whereof I aix my signature.

DAVID H. LAMAR.

